I have been a long standing customer of Sprint and bought 4 new iPhone 4s, the quality of the service in terms of data speed and converge are completely unacceptable and after over 10 years with sprint I will be going to att. I just bought all these phones and out of 14 day return. Is there a way I can make these all work on att? cause I noticed ALL 4s are identical in terms of radios and things, the activation screen and sim determine the carrier logo on top I would love to make these work on att so i can have my full eligibility when the new iPhone comes out in june for all my lines. any luck or recommendations ?